Sometimes 
is used to emphasize that the space is Euclidean. This could mean, for example, that the space comes with an inner product (I have seen this used at least once). The particular meaning of the notation is not standard across all disciplines. As to whether the space is the same, topologically the answer is yes, but the notation can be used to clarify what use the space is being put to.
Sometimes is used to emphasize that the space is Euclidean. This could mean, for example, that the space comes with an inner product (I have seen this used at least once). The particular meaning of the notation is not standard across all disciplines. As to whether the space is the same, topologically the answer is yes, but the notation can be used to clarify what use the space is being put to.
probably stands for Euclidean.
Quoting from Wikipedia:
Mathematicians denote the
-dimensional Euclidean space by
if they wish to emphasize its Euclidean nature, but
is used as well since the latter is assumed to have the standard Euclidean structure, and these two structures are not always distinguished
The R expression
exp(1)
represents e, and
exp(2)
represents e^2.
This works because exp is the exponentiation function with base e.
-digamma(1) is the Euler's Constant in R.
e, (exp(1) in R), which is the natural base of the natural logarithm
Euler's Constant. Euler's Number
Videos
The "e" is a symbol for base-10 scientific notation. The "e" stands for $\times 10^{\rm exponent}$. So -1.861246e-04 means $-1.861246 \times 10^{-4}$. In fixed-point notation that would be -0.0001861246.
This notation is pretty standard. Even Microsoft Excel understands it, not just R.
I cannot yet comment so this answer will be a response to @Mark L. Stone : OP also stated that he's getting covariance matrix values in the scientific notation. Obviously the negative value must be one of the covariances.
To not be completely OT I will just add that working with scientific notation to me looks a bit clunky(especially if you are publishing the results). To supress the notation in R use the command options(scipen=alpha) where alpha is the maximum number of digits for the result to be still expressed in fixed notation.